feat(ui): one CountBadge for all counters; counters on tab corners

- CountBadge component (accent / muted, inline / corner, 99+, showZero);
  used in the nav bar, task list and list tabs, admin organizations and
  numeric badges of the mobile menu; old badge-count removed
- Counters sit on the top right corner of tabs; "Alle Aufgaben" gets one
  (desktop tab and mobile menu)
- Open/done task counters include tasks in shared lists, matching what
  "Alle Aufgaben" shows (nav counter was too low)
- Theme template derives --accent-dim/--accent-border from the accent
- Docs: ui-patterns counters section

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/features/triage/TasksView.tsx

@@ -32,6 +32,7 @@ import { UnifiedShareModal } from '../../components/UnifiedShareModal';
 import { TaskDetailModal } from './TaskDetailModal';
 import { ManageColumnsModal, DEFAULT_KANBAN_COLUMNS } from './ManageColumnsModal';
 import { AvatarStack, AvatarPerson } from '../../components/AvatarStack';
+import { CountBadge } from '../../components/CountBadge';
 import { useMobileActions } from '../../context/MobileActionContext';
 
 interface TasksViewProps {
@@ -40,6 +41,7 @@ interface TasksViewProps {
   onOpenDocument: (docId: string, blockId?: string) => void;
   refreshTrigger?: number;
   initialSelectedTaskId?: string | null;
+  openTasksCount?: number; // all open tasks incl. shared lists (same as the nav bar counter)
 }
 
 export const TasksView: React.FC<TasksViewProps> = ({
@@ -48,6 +50,7 @@ export const TasksView: React.FC<TasksViewProps> = ({
   onOpenDocument,
   refreshTrigger = 0,
   initialSelectedTaskId,
+  openTasksCount,
 }) => {
   const [viewMode, setViewMode] = useState<'list' | 'kanban'>('list');
   const [filter, setFilter] = useState<'open' | 'done' | 'discarded'>('open');
@@ -1036,6 +1039,7 @@ export const TasksView: React.FC<TasksViewProps> = ({
         id: 'list-all',
         label: 'Alle Aufgaben',
         icon: <Layers className="w-4 h-4" />,
+        badge: openTasksCount || undefined,
         active: selectedListId === 'all',
         onClick: () => setSelectedListId('all'),
       },
@@ -1086,6 +1090,7 @@ export const TasksView: React.FC<TasksViewProps> = ({
     safeDiscarded.length,
     kanbanTasks.length,
     safeTaskLists,
+    openTasksCount,
     currentSelectedList,
     isSelectedListReadOnly,
     setPrimaryAction,
@@ -1368,17 +1373,18 @@ export const TasksView: React.FC<TasksViewProps> = ({
     <div className="w-full space-y-3">
       {/* Top Header: Task Lists Tabs & View Mode Switcher (Desktop) */}
       <div className="hidden sm:flex flex-wrap items-center justify-between gap-2 border-b border-border pb-2 !mt-0">
-        {/* Task Lists selector tabs */}
-        <div className="flex flex-wrap items-center gap-1">
+        {/* Task Lists selector tabs (counters sit on the top right corner, hence the extra gap) */}
+        <div className="flex flex-wrap items-center gap-x-3 gap-y-3 pt-2">
           <button
             onClick={() => setSelectedListId('all')}
-            className={`h-8 px-3 text-xs font-medium border rounded-btn transition-colors ${
+            className={`relative h-8 px-3 text-xs font-medium border rounded-btn transition-colors ${
               selectedListId === 'all'
                 ? 'bg-panel border-accent text-main'
                 : 'bg-canvas border-border text-muted hover:text-main'
             }`}
           >
             Alle Aufgaben
+            <CountBadge count={openTasksCount} position="corner" />
           </button>
 
           {safeTaskLists.map((tl) => (
@@ -1394,9 +1400,7 @@ export const TasksView: React.FC<TasksViewProps> = ({
               >
                 <span>{tl.icon}</span>
                 <span>{tl.title}</span>
-                {tl.tasksCount !== undefined && tl.tasksCount > 0 && (
-                  <span className="ml-1 badge-count">{tl.tasksCount}</span>
-                )}
+
                 {(() => {
                   const isShared = (tl.shares && tl.shares.length > 0) || (tl.members && tl.members.length > 1);
                   if (!isShared) return null;
@@ -1418,6 +1422,7 @@ export const TasksView: React.FC<TasksViewProps> = ({
                   );
                 })()}
               </button>
+              <CountBadge count={tl.tasksCount} position="corner" />
               {selectedListId === tl.id && (
                 <button
                   onClick={() => handleDeleteTaskList(tl.id)}